title: Dysanaptic growth of lung and airway in children with post-infectious bronchiolitis obliterans.
abstract: BACKGROUND
  Post-infectious bronchiolitis obliterans (PBO) is a rare form of chronic obstructive lung disease associated with small airway fibrosis following a severe insult to the lower respiratory tract. It has been suggested that PBO is a non-progressive disease. However, evidence supporting this statement is limited. In this case series, we sought to determine the changes of pulmonary function tests (PFT) over time in children with PBO.
  
  
  METHODS
  Seven children with PBO, ages 6-15 years old, were retrospectively studied between 1994 and 2012. Spirometry and lung volumes tests were performed in accordance with American Thoracic Society (ATS) guidelines and were monitored over time. The average rate of change was calculated using generalized linear mixed models.
  
  
  RESULTS
  The median baseline values for forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), the FEV1/FVC ratio and forced expiratory flow 25%-75% (FEF25%-75%) were 57%, 50%, 87% and 29%, respectively. FVC increased at a rate of 1.8% per year (P = 0.008). There was no significant change in FEV1 over time (P = 0.112). However, the FEV1/FVC ratio decreased by 2.6% per year (P < 0.001).
  
  
  CONCLUSIONS
  PFT in childhood PBO was characterized by significant airway obstruction. Over time, FVC (lung parenchyma) increased and FEV1 (airway) remained stable, but FEV1/FVC ratio declined more than expected, suggesting a mismatch in the growth of the airway and lung parenchyma (dysanaptic growth). Further studies in larger populations are needed to validate these observations.
authors.affiliation: Division of Pulmonary Medicine, Department of Pediatrics, University of Texas Medical School at Houston, Houston, TX, USA.
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Mosquera
authors.forename: Syed S
authors.initials: SS
authors.lastname: Hashmi
authors.forename: Susan E
authors.initials: SE
authors.lastname: Pacheco
authors.forename: Alexandra
authors.initials: A
authors.lastname: Reverdin
authors.forename: Justyna
authors.initials: J
authors.lastname: Chevallier
authors.forename: Giuseppe N
authors.initials: GN
authors.lastname: Colasurdo
mesh_terms: D000293:Adolescent; D001989:Bronchiolitis Obliterans / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology*; D002648:Child; D018450:Disease Progression; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007249:Inflammation / Q000473:pathology / Q000503:physiopathology; D008168:Lung / Q000473:pathology / Q000503:physiopathology; D008297:Male; D012129:Respiratory Function Tests; D012141:Respiratory Tract Infections / Q000150:complications; D014057:Tomography, X-Ray Computed / Q000379:methods; D014797:Vital Capacity
keywords: bronchiolitis obliterans; dysanaptic growth; immunomodulation; inhaled corticosteroids; pulmonary function test